Green synthesis of graphene by using tomato juice

Abstract

Embodiments of the present invention encompass methods of forming graphene from graphene oxide and/or graphite oxide using tomato juice.

What is claimed is: 
     
       1. A method comprising:
 forming a suspension comprising a solvent and a product of oxidation of graphite, the product of oxidation of graphite comprising graphene oxide, graphite oxide, or a combination thereof;
 wherein the graphene oxide, the graphite oxide, or the combination thereof comprise about 0.01 wt % to about 25 wt % of the suspension; 
 
 adding fresh tomato juice to the suspension; 
 exfoliating the product of oxidation of graphite, exfoliating graphite during formation of the product of oxidation of graphite, or a combination thereof; 
 after exfoliation, allowing the suspension with added fresh tomato juice to sit quiescently for a time period at a temperature in the range of about 18° C. to about 25° C. to form a solid product, the solid product comprising the exfoliated graphene oxide, the exfoliated graphite oxide, or both, that have been at least partially reduced to graphene; 
 after the time period, separating the solid product comprising graphene from the suspension with added fresh tomato juice. 
 
     
     
       2. The method of  claim 1 , wherein the exfoliation comprises ultrasonication. 
     
     
       3. The method of  claim 2 , wherein the suspension with added fresh tomato juice is subjected to ultrasonication. 
     
     
       4. The method of  claim 2 , wherein ultrasonication is executed for at least 45 minutes. 
     
     
       5. The method of  claim 1 , wherein the solvent comprises water. 
     
     
       6. The method of  claim 5 , wherein 99 wt % of the suspension consists of water and the product of oxidation of graphite. 
     
     
       7. The method of  claim 1 , wherein the fresh tomato juice is added to the suspension within 45 minutes of the juice being squeezed from the tomato. 
     
     
       8. The method of  claim 1 , wherein the fresh tomato juice is free of additives. 
     
     
       9. The method of  claim 1 , wherein the fresh tomato juice is not diluted with other liquids before being added to the suspension. 
     
     
       10. The method of  claim 1 , wherein the weight ratio of the amount of fresh tomato juice added to the amount of the suspension is about 2:1 to about 1:2. 
     
     
       11. The method of  claim 1 , wherein the time period is not less than 22 hours, and not more than 30 hours. 
     
     
       12. The method of  claim 1 , wherein the graphene oxide, the graphite oxide, or the combination thereof comprise about 0.1 wt % to about 15 wt % of the suspension. 
     
     
       13. The method of  claim 1 , wherein the graphene oxide, the graphite oxide, or the combination thereof comprise about 0.2 wt % to about 5 wt % of the suspension. 
     
     
       14. A method comprising:
 forming a suspension comprising a solvent and a product of oxidation of graphite, the product of oxidation of graphite comprising graphene oxide, graphite oxide, or a combination thereof;
 wherein the graphene oxide, the graphite oxide, or the combination thereof, and the solvent comprise at least 95 wt % of the suspension; 
 
 adding fresh tomato juice to the suspension; 
 exfoliating the product of oxidation of graphite, exfoliating graphite during formation of the product of oxidation of graphite, or a combination thereof; 
 after exfoliation, allowing the suspension with added fresh tomato juice to sit quiescently for a time period at a temperature in the range of about 18° C. to about 25° C. to form a solid product, the solid product comprising the exfoliated graphene oxide, exfoliated graphite oxide, or both, that have been at least partially reduced to graphene; 
 after the time period, separating the solid product comprising graphene from the suspension with added fresh tomato juice. 
 
     
     
       15. The method of  claim 14 , wherein the exfoliation comprises ultrasonication. 
     
     
       16. The method of  claim 15 , wherein the suspension with added fresh tomato juice is subjected to ultrasonication. 
     
     
       17. The method of  claim 15 , wherein ultrasonication is executed for at least 45 minutes. 
     
     
       18. The method of  claim 14 , wherein the solvent comprises water. 
     
     
       19. The method of  claim 18 , wherein 99 wt % of the suspension consists of water and the product of oxidation of graphite. 
     
     
       20. The method of  claim 14 , wherein the graphene oxide, the graphite oxide, or the combination thereof comprises about 0.1 wt % to about 3.0 wt % of the suspension. 
     
     
       21. The method of  claim 14 , wherein the fresh tomato juice is added to the suspension within 45 minutes of the juice being squeezed from the tomato. 
     
     
       22. The method of  claim 14 , wherein the fresh tomato juice is free of additives, and the fresh tomato juice is not diluted with other liquids before being added to the suspension. 
     
     
       23. The method of  claim 14 , wherein the weight ratio of the amount of fresh tomato juice added to the amount of the suspension is about 2:1 to about 1:2. 
     
     
       24. The method of  claim 14 , wherein the time period is not less than 22 hours, and not more than 30 hours. 
     
     
       25. A method comprising:
 forming a suspension comprising a solvent and graphite oxide, and the suspension optionally comprising graphene oxide;
 wherein about 0.01 wt % to about 25 wt % of the suspension is graphite oxide, or if graphene oxide is present, about 0.01 wt % to about 25 wt % of the suspension is graphite oxide and graphene oxide; 
 
 adding fresh tomato juice to the suspension; 
 exfoliating the graphite oxide, and optionally, the graphene oxide, if present; 
 after exfoliation, allowing the suspension with added fresh tomato juice to sit quiescently for a time period at a temperature in the range of about 18° C. to about 25° C. to allow for the formation of a solid product, the solid product comprising graphene, at least a portion of the graphene resulting from at least partial reduction of the exfoliated graphite oxide, and, if present, the exfoliated graphene oxide; 
 after the time period, separating the solid product comprising graphene from the suspension with added fresh tomato juice. 
 
     
     
       26. The method of  claim 25 , wherein the suspension with added fresh tomato juice is subjected to ultrasonication and the ultrasonication is executed for at least 5 minutes and not more than 6 hours. 
     
     
       27. The method of  claim 25 , wherein the solvent comprises water, and at least 99 wt % of the suspension consists of water and graphite oxide, or, if graphene oxide is present, at least 99 wt % of the suspension consists of water and graphite oxide and graphene oxide. 
     
     
       28. The method of  claim 25 , wherein about 0.1 wt % to about 15 wt % of the suspension comprises graphite oxide, or if graphene oxide is present, about 0.1 wt % to about 15 wt % of the suspension comprises a combination of graphite oxide and graphene oxide. 
     
     
       29. The method of  claim 25 , wherein the fresh tomato juice is added to the suspension within 45 minutes of the juice being squeezed from the tomato. 
     
     
       30. The method of  claim 25 , wherein the fresh tomato juice is free of additives, and the fresh tomato juice is not diluted with other liquids before being added to the suspension. 
     
     
       31. The method of  claim 25 , wherein the weight ratio of the amount of fresh tomato juice added to the amount of the suspension is about 2:1 to about 1:2. 
     
     
       32. The method of  claim 25 , wherein the time period is not less than 22 hours, and not more than 30 hours. 
     
     
       33. A method comprising:
 forming a suspension comprising a solvent and graphite oxide, and the suspension optionally comprising graphene oxide; 
 adding fresh tomato juice to the suspension; 
 sonicating the suspension before, after, and/or during the addition of fresh tomato juice; 
 after sonication, allowing the suspension with added fresh tomato juice to sit quiescently for a time period at a temperature in the range of about 18° C. to about 25° C. to allow for the formation of a solid product, the solid product comprising graphene, at least a portion of the graphene resulting from at least partial reduction of the exfoliated graphite oxide, and, if present, the exfoliated graphene oxide; 
 after the time period, separating the solid product comprising graphene from the suspension with added fresh tomato juice. 
 
     
     
       34. The method of  claim 33 , wherein the solvent comprises water, and at least 99 wt % of the suspension consists of water and graphite oxide, or, if graphene oxide is present, at least 99 wt % of the suspension consists of water and graphite oxide and graphene oxide. 
     
     
       35. The method of  claim 33 , wherein about 0.2 wt % to about 5.0 wt % of the suspension comprises graphite oxide, or if graphene oxide is present, about 0.2 wt % to about 5.0 wt % of the suspension comprises a combination of graphite oxide and graphene oxide. 
     
     
       36. The method of  claim 33 , wherein the weight ratio of the amount of fresh tomato juice added to the amount of the suspension is about 2:1 to about 1:2. 
     
     
       37. The method of  claim 33 , wherein the time period is not less than 22 hours, and not more than 30 hours.